Can a healthy diet help you with skin disorders like acne vulgaris? There is a lot of discussion going around whether certain foods (like dairy) will help or worsen your skin. A recent study went looking for a connection between soybeans and acne (including blackheads) on women.

soybean in hand

Soybeans are a great source of oils and proteins. It is a dietary substitution for animal products for vegans. Soy is one of the rare plants that provides a complete protein. The term complete protein means the soybean plant contains all 9 amino acids essential for human nutrition. While there are a total of 20 amino acids, there are 9 the body can’t produce on its own.

Soy for skin problems

1.) Introduction

Soy is the richest source of isoflavone. Isoflavone is a compound with estrogenic activity (phytoestrogens).

The purpose of the study is to prove if oral soy isoflavone works as an anti-androgen on women and if it will reduce acne vulgaris. An anti-androgen blocks the effect of male hormones like dihydrotestosterone (DHT) and testosterone.

2.) Method

Before the study started, all samples were already using 0.025% tretinoin cream and a sunscreen with SPF15. Both control and treatment group will keep on using this during the trials.

The control group was given a placebo of 0 mg soy isoflavone. The treatment group was given a daily dosage of 160 mg soy isoflavone. Each group consists of 20 persons and the treatment lasts 12 weeks.

3.) Results

Soybeans against acne and blackheads

AV lesion

The lesion of acne vulgaris was measured as the amount of nodules, pustules, open comodomes(blackheads) and closed comodomes on a person.


The acne vulgaris lesion of the control group has barely changed while the treatment group shows a significant difference.

DHT levels

The dihydrotestosterone levels were also measured to find a correlation between acne vulgaris and DHT levels.

dht levels

As shown here, before the treatment the DHT levels were close to eachother. After the treatment we can see that the levels of DHT are significantly lower in the treatment group.

The Spearman correlation test concluded that there was a strong connection between the levels of DHT and the AV lesions.


The study concludes that as a result of decreasing DHT levels, the amount of acne vulgaris lesion will significantly lower. While we can only say with certainty that this works on women who are also receiving 0.025% tretinoin and using an SPF15 sunscreen.

We can’t conclude for certain, but we certainly can suggest that soybeans will help you fight acne and blackheads without using tretinoin.

Authors of the study: Puguh Riyanto, Prasetyowati Subchan, and Rosa Lelyana